None of what you surmise is true. For the answer, I suggest you and others read "If the keel broke open on the surface then whatever coal was in that compartment would surely spill out long before both sections separated on the surface and sank. Frank Osman saw lumps of coal shooting out of the funnels during the break up and I'm guessing there must have been an enormous release of coal somewhere in the vicinity of the break up.
Archaeology of Titanic by James P. Delgado Volume 65 Number 3, [bcolor=rgb(252, 252, 255)]May/June 201[/bcolor]. It can be found at Archaeology of Titanic - Archaeology Magazine Archive
In the following quote I show th relevant part in bold.
"The new map revealed to us that the scattered features and artifacts do not represent everything that once lay inside or on the ship. Rather than streaming like comet tails from the bow and stern as the ship sank, most contents of the artifact field come from the full disintegration of a section of the ship—some 70 feet of Titanic’s 882-foot length that branched up and out between two of the deck funnels. Broken pieces of the hull from that section were accompanied by two of the reciprocating engine cylinders, the five boilers from the number one boiler room, 51 tons of coal (of 1,000 or more tons on board), and four tons of coke. This segment also included the contents of the Verandah Café, the Palm Court, the aft end of the First Class Lounge, and a group of first-, second-, and third-class cabins, as well as the galleys and pantries, sculleries, wine room, barber shop, smoking room, hospital, cold storage rooms, silverware locker, and baker’s shop. Among these items on the seafloor are also pieces swept from the deck, such as the funnels, the davits used to launch lifeboats, and the remains of the bridge."